Understanding growth and puberty using the RCPCH UK
2-18 growth charts
Why measure school aged children?• Growth is best indicator of health• Demonstration of normality of growth
by age and stage of puberty• Identify disorders of growth• Assess obesity
Key questions• Is a child too short or tall for their age – could
there be a problem?• Has puberty started and is it progressing
normally?• Is growth normal for stage of puberty?• Is this child overweight or obese?
The new UK 2-18 charts will help you answer these questions
• Developed and published by RCPCH • Based on updated UK 1990 growth references• New design features:
• Puberty Phases• BMI lookup and plotting grid • Parental height comparator • Adult height prediction
RCPCH UK 2-18 Growth chart
UK90 reference after age 4
WHO standards until age 4
Birth centiles
Predicted adult height scale
Parent height comparator
Mid parental centile scale
Use an X to mark the child’s most recent height centile in the centre line
Read off the child’s estimated adult height from right scale
80% of children will be within ±6 cm of this value
Scale also shown in feet and inches on left
Using the Adult Height Predictor
x
Mark mother’s height on the left hand scale and father’s height on the right scale using arrows
Draw a line between arrowheads and read off mid-parental centile where this crosses the central line
Regression adjustment means that children of very short or tall parents have mid parental centile nearer to average than expected
Using the Parent Height Comparator
Mid parental Centile = 75th
Compare the mid-parental centile to the child’s current height centile (x)
Nine out of ten children’s height centiles are within ±two centile spaces of the mid-parental centile
Only 1 percent more than three centile spaces below
Using the Parent Height Comparator
Mid parental centile = 75th
X within parental range
X < 5% children
< 1% children X
Interpretation of the mid-parental height centile (MPHC)• Average centile for all children of these parents • Compare to child’s actual height centile • Most children are within ±two centile spaces of
the mid-parental centile• Only 1 percent more than three centile spaces
below– Most have no treatable cause for their short stature, – Investigate further if other concerns about the child’s
growth• NB a child growing abnormally may still be within
mid-parental height range
Body Mass Index (BMI) lookup
• Read weight and height centiles from the growth chart.
• Plot weight centile (left axis) against the height centile (bottom axis)
• Read off the corresponding BMI centile from the slanting lines
• Record centile on grid at top of chart
• Accurate to ¼ centile space
BMI =
91st centile
BMI centile grid: plotting example
>91st centile suggests overweight>98th centile is very overweight (clinically obese)
BMI Interpretation• A child whose weight is average for their height
will have a BMI between the 25th and 75th centiles
• < 2nd centile may reflect undernutrition, but may simply reflect a small frame or low muscle mass
But • BMI often varies from one measurement to the
next due to measurement error• Compare BMI to weight and height centiles
using BMI plotting grid at top of chart
Pre-puberty ONLY
Puberty starting before 8 is precocious
Growth during Puberty
Plotting pubertal children on the UK 2-18 Growth charts
The 3 Phases of Puberty: from historyPre-puberty(Tanner stage 1)
In Puberty (Tanner stage 2-3)
Completing Puberty(Tanner stage 4-5)
Girls If all of the following:
No signs of pubertal
development
If any of the following:
Any breast enlargement pubic or axillary hair
If all of the following
Started periods with signs of pubertal development
Boys If all of the following:
High voice and
No signs of pubertal development
If any of the following:
Slight deepening of the voice
Early pubic or axillary hair growth
Enlargement of testes or penis
If any of the following:
Voice fully broken
Facial hair
Adult size of penis with pubic and axillary hair
Most healthy children start puberty between these ages
Most healthy children complete puberty between these ages
Pu
berty
Lin
es• Puberty Lines mark
boundaries of normal pubertal development
• Shaded zone marks area where 0.4th centile varies with phase of puberty
Puberty section of new 2-18 Chart
Shaded Puberty Zone
• Marks area where 0.4th centile varies with phase of puberty
• Heights in the shaded area below the 0.4th centile:– Pre-puberty: if within 2 centiles
of Mid-Parental Height = within the normal range
– In or Completing puberty = below normal range
Summary: 2-18 charts will help you assess• The phases of puberty and how to
use them to interpret growth charts
• Predict adult height and relate a child’s height to the parents’ height
• Assess BMI without a calculator